Process and apparatus for melting iron



June 22 1926.

,. Y. A. DYER PROCESS AND APPARATUS FOR MELTING IRON Filed Feb. 4. 19,25

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Patented June 22, 1926.

UNITED" STATES PATENT orrlcs.

Y'ULEE A. DYER, or ,cavn srame, cacao 1a.

rnocnss am) arrm'rus iron. manure mon.

Application filled rebruary 4, 1925. Serial No. 6,784.

contemplates an apparatus wherein there is one cupola or furnace inwhich a portion of the metal is melted and a second adjoining cupola orfurnace to which the waste prodnets of combustion from the first cupolaor furnace areconveyed and passed through a layer of fuel .in thepresence of additlonal metal to be melted.

' In this way the quantity of fuel required in. the second cupola orfurnace in particular, is automatically reduced approximately fifty percent, and the quantity of sulphur and other undesirable. elementscontained in the fuel, are likewise greatly precluded from contaminatingthe metal. This results n a higher grade product being obtained fromboth the first and second cupola or furnace, but especially morepronounced from the second cupola orfurnace.

In the preferred method of practicing the present invention, alternatelayers or charges of solid carbonaceous materialto be combusted andmetal to be melted are placed in the first cupola or furnace, into whicheither cold or preheated air is blown, the air entering the cupola orfurnace under the lowermost layer or bed of carbonaceous materialthrough which it is forced to produce combustion to melt the' upperlayers of metal within the cupola or furnace chamber. The hot escapinggases given off from the first cupola or furnace are th conveyeddirectly into a second cupola or furnace unit, through a conduitconnecting the two units. Transference of these hot gases is aided bymechanically produce pressure, the gases first entering a gas beltsurrounding the second on ola or furnace, and then enter interior 9cupola o1. furnace from said belt by way of a series of ports.encircling the second cupola or furnace. These ports are located in thecupola or furnace wall at a point where the hot gases will enter below,and then pass through a comparatively thin bed of caras bonaceousmaterial which is combusted to melt relatively large layers of metal inthe second cupola or furnace, the layers of carbonaceous material andmetal in the second cupola or furnace bein arranged alter- '00 nately asin the first cupo a or furnace.

This process, which may be termed a twin-unit process, or ,automaticrecuperation process, may be racticed in various types of apparatus, t especific form shown in the present instance being illustrative only andhighly diagrammatic.

The figure in the drawing is a general cross section, partly in sideelevation, through the two melting units and their accessories.

As illustrated in the drawings, there is a melting cupola or meltingfurnace 10 closed at-the top, the fuel and metal to be melted being'fedinto the combustion chamber of the cupola or furnace through a valvetype charging box 12 of either automatic or hand type regulation. Itwill be understood that a bed charge or layer of fuel is first fedthrough the door 12, then a la er of metal to be melted, and theninterme iate layers of fuel and metal, alternately. The second cupola orfurnace, or meltin unit, is indicated at 13, the wall of this unit beingprovided with suitably aligned chargin doors 14;, 15, through whichlayers of fue and metal to be melted may be fed either automatically, orby hand, so as to place alternate layers of the fuel and metal in thecombustion chamber of the cupola or furnace, the bottom la r or bed inthis cupola or furnace also ing of carbonaceous fuel.

Either cold or preheated air for aiding combustion in the first cupolaor furnace is 5 delivered by any desirable mechanism to and through awindpipe 16' communicating with a windbox 17 surround ng said cu ola orfurnace, from which box the air flows into the interior of the cupola orfurnace through a plurality of tuyeres 18 arranged around the cupola orfurnace wall in accordance with the usual practice. Surrounding the baseof the second cupola or furnace 13 is a gas belt 19, which communicateswith the interior of the cupola or furnace through a seriesof ports 20in the cupola or furnace wall. The hot waste gases passing off from thecupola or furnace 10 are adapted to be removedand conveyed to this gasbelt 19, from which they will flow into the second cupola or furnace 13at a point beneath the lower layer of fuel in the latter, for burning orrecuperation purposes. Preferably the passage 22, through which thegases flow from cupola or furnace 10 to gas belt 19, is so arran ed withrespect to cupola or furnace 10 that the wall of the latter willfunction as a baflie 21, over which the gases must pass before reachingthe gas belt 19. However, if desired, a plurality of ports 21 may beprovided in the wall 21 of the cupola or furnace so that said gases mayflow more directly into the passage 22. To .aid combustion in the secondcupola or furnace 13 suitable air connections, indicateddiagrammatically by the air inlet pipe 23, may be provided for supplyingair to the passage 22. i

The general operating plan or method practiced with this meltingapparatus is as follows: The melting process in cupola or furnace 10consists of charging alternate layers of carbonaceous material andmetal, the lowerniost layer or bed being one composed of carbonaceous.material. This lower layer of fuel approximates a depth of abouttwenty-two inches above the tuyeres 18. Upon combustion of the fuel inthe cupola or furnace 10 the metal, which will become molten, and theusual slag, will pass out of a tap hole. and flow down the tap spout 24to the usual container, such as ladle 25, the slag being forced over thetop of the side f the spout by the ordinary skim method. Thewaste'gases, which would ordinarily pass off unused from cupola orfurnace 10, are conveyed through the passage 22, either after passingover or through baflle wall 21, to the gas belt 19, the proper quantityof free or excess air oxygen.(if necessary) to carry on combustioh inthe second cupola or furnace 13 having, in the meantime,been deliveredto the said gases through the air supply'connection 23. From the gasbelt 19, the gases, with the combined air, pass through the" ports 20into. the second cupola or furnace 13, where they not only aid incombusting the carbonaceous fuel inthe second cupola or furnace, butalso supply sensible heat units to assist in heat mg aud melting uppermetal charges in the second cupola or furnace. The metal thus melted inthe second cupola or furnace consistently flows from the cupola orfurnace proper through an outlet 26 into the forehearth 27 and isfinally tapped out at spout 28 into a container such as a bull ladle 29.

By utilizing the sensible heat units supplied by the waste hot gasescoming into the second cupola or furnace, the layers of fuel used inthat cupola or furnace, are, as a natural sequence to such operation,quite thin compared to those in the first cupola or furnace; the totalquantity of fuel consumed in the melting process carried on in thesecond cupola or furnace, is thereby greatly reduced, this reductionamounting to approximately sixty per cent, by weight, in the case of thefirst lowermost layer or bed, and fifty per cent, by weight, insubsequent or intermediate charges of fuel. This natural reduction inthe quantity of fuel consumed, is quite an advantage in that the cost ofoperation is greatly curtailed, but this is by no means the onlyadvantage resulting from the present process. A second resultingadvantage, and a worthy one, lies in the improved quality of the meltedmetal obtained from the second cupola or furnace. .The metal obtainedfrom the second cupola or furnace has been found, in actual practice, tobe more dense and homogeneous, making a product that'can be easilymachined and which possesses an increased strength approximating fiftyper cent to sixty per cent over metal melted in an ordinary single-unitcupola or furnace. This highly desirable result is obtained by reason ofthe fact that such a small quantity of sulphur and other contaminatingelements is present in the second cupola or furnace. That is. thequantity of fuel necessary to be used in the second cupola or furnacehaving been re duced approximately one-half, the quantity of sulphur andother contaminating elements, which are a residue of burned fuel, arenot absorbed by the metal being melted in that cupola or furnace. If,and when, desired, the metal from the two cupolas or furnaces may beconveyed to asinglecontainer, thereby makirg a mixture of any desiredanalysis within the scope of rational cupola practice.

lVhat I claim is:

1. The process of melting metal, which consists in charging onecombustion chamber with a comparatively deep bed of carbonaceousmaterial, combusting said material in the presence of a supply of airand a body of metal to be melted, and then transferring or conveying thehot waste gases from said chamber directly to a second combustionchamber and there passing said hot waste gasesunder and throughacomparatively thin layer of carbonaceous material in the presence ofadditional metalto be 1,5ee,uee

melted, whereby the uantity of fuel required in said second c amber ismaterially reduced.

2. The process of melting metal, which consists in charging onecombustion chamber with a comparatively deep bed ofcarbonaceousmaterial, combusting said material in the presence of a supply of airand a body of metal to be melted, conveying the hot waste gasesdirectlyto a second combustion chamber, introducing a supply ofadditional air to said gases at a point intermediate the two chambers,and then passing said gases and additional air under and through acomparatively thin layer of carbonaceous material in the resence ofadditional metal to be melted, w ereby the guantity of car-,

bonaceous material require in the second chamber and the quantity ofsulphur and other contaminating elements coming in contact with themetal in said second chamber, are materially reduced.

3. The process of melting metal, which I consists in charging onecombustion chamber with a comparatively deep bed of carbona ceousmaterial, above which layers of metal to be melted and carbonaceous fuelto be combusted, are arranged alternately, combusting said carbonaceousmaterial in the 1; presence of a supply of air and the body of metal tobe melted, and then transferring, or conveying, thehot waste gases fromsaid chamber directly to a second combustion chamber, and there passingsaid hot waste gases under and through a comparatively thin layer ofcarbonaceous material, above which several alternate layers of metal tobe melted and thin layers of carbonaceous fuel to be combusted, arearranged alternately,

whereby the quantity of fuel required in said second chamber ismaterially reduced,

and the quality of the melted metal is materially improved.

4. The process of melting metal, which consists in charging onecombustion chamber with a comparatively deep bed of carbonaceousmaterial, above which are alternately placed layers of metal to bemelted and layers of carbonaceous fuel to be combusted, res ectively,combusting said carbonaceous ma erial in the presence of a supply of airand a body of metal to be-me-lted, conveying the hot waste gases, afterthe same have served their purpose in said combustion chamber, from saidcombustion chamber directly into a second combustion chamber,introducing a supply of additional air to said gases at a pointintermediate the said two chambers, and then passing said gases 5 andadditional air under and through a comparatively thin bed ofcarbonaceous material, above which are arranged, or placed, alternatelayers of metal to be melted and thin layers of carbonaceous materialtobe combusted, whereby the quantity of carbonacarbonaceous material,coming in contact with the metal in said second chamber, are materiallyreduced, and the quality of the metal melted in said second chamberis'materially improved.

5. The process of melting 'metal, which consists in charging onecombustion chamber with a comparatively deep bed of carbonaceous fuel,above which are placedalternate layers of metal to be melted andcarbonaceous fuel, so that a layer of said metal to be melted willalways remain above a layer of said carbonaceous fuel to be combusted,combusting said carbonaceous fuel in thepresence of a layer of saidmetal to be melted and a supply of air forced into said combustionchamber under mechanical pressure, conveying the hot waste gases fromsaid combustion chamber directly to a sec: ond combustion chamber,introducing a sup-. ply of additional air to said gases at a pointintermediate the two said chambers, and then passing said gases andadditional air into a second combustion chamber containing a thin lowerlayer, orbed, of carbonaceous fuel, directly above which are arranged,first, a layer of metal to be melted, and then alternate thin layers ofcarbonaceous fueland metal to be melted, so that a thin layer of saidcarbonaceous fuel will always remain immediately under and against oneof said layers of metal, which said waste gases andadditional air sopassed into said combustion chamber are forced under and through saidalternate layers of carbonaceous fuel to be combusted and metal to bemelted, in said second combustion chamber, whereby the quantity ofcarbona-v ceous fuel required in the said second combustion chamber andthe quantity of sulphur and other contaminating elements coming incontact with said metal to be melted in said second combustion chamberare materially reduced.

6. The process of melting metal, which consists in charging a cupolafurnace with a comparatively deep bed of carbonaceous material,combusting said material in the presence of a supply of air and a bodyof metal to be melted, and then transferring or conveying the hot wastegases from said cupola to the combustion chamber of a second cupola andthere passing said hot waste gases under and through a comparativelythinlayer of carbonaceous material in the presence of additional metalto .be melted,

whereby the Zquantity of fuel required in terial, combusting saidmaterial in th 3 presence of a sup ly of air and a body of metal to bemelte conveying the hot waste gases to the second cupola furnace,introducing a supply of additional air to said hot waste gases duringtheir travel from the first cupola to the second cupola, and thenpassing said hot waste gases and additional air through a comparativelythin layor of carbonaceous material in the presence of additional metalto be melted, whereby the quantity of carbonaceous material required inthe second chamber and the quantity of sulphur and other contaminatingelements coming in contact with the metal in the second cupola arematerially reduced.

. YULEE A. DYER.

